Conventional assembly (also referred to as PTH or Plated Through-Hole) is the more traditional method of populating Printed Circuit Boards (PCBs). The component leads are placed through a pre-drilled hole on the bare printed circuit board. The components can be soldered into place either by hand soldering (with a soldering iron), or by the use of a wave flow soldering system. Flow soldering is the preferred method for medium to large production volumes and is used (where possible), to reduce process times and therefore assembly costs.

While this method of assembly has reduced over recent years due to the emergence and necessity of SMT,  it can still often be considered as the preferred method for products used within harsh environments or components .  The intrinsic mechanical strength of through-hole assembly provides additional support to the component in high stress applications where shock, vibration and high temperature conditions exist.